1. Field of the Invention
The present invention is related to a display apparatus for use with an image forming apparatus, and more particularly to a technology to display operation screens (UI screens) of functions implemented in the image forming apparatus at the display apparatus.
2. Description of the Related Art
An image forming apparatus, which implements a plurality of applications for a copier, a printer, a facsimile, and a scanner, includes a GUI (Graphical User Interface) used for function settings, and display screens (application screens) which correspond to function units and display information concerning functional operations. Moreover, the image forming apparatus includes a window system for displaying various screens in response to an operation state and a user request. Accordingly, the display apparatus with which the image forming apparatus is equipped has been functionally highly developed.
In the image forming apparatus, for example, as disclosed in Japanese Laid-open Patent Application No. 2003-283717, an operation screen, which includes a plurality of graphic parts (hereinafter, called “display components”) and is high function, can be displayed. Japanese Laid-open Patent Application No. 2003-283717 presents an image forming apparatus which implements a terminal display application and a terminal emulator and displays a GUI (Graphical User Interface) such as a software keyboard or a like at a display apparatus with which the image forming apparatus is provided.
However, there are problems described below in the conventional image forming apparatus.
The conventional image forming apparatus disclosed in the Japanese Laid-open Patent Application No. 2003-283717 implements software and carries out various functions. Software for controlling a display apparatus is an OCS (Operation panel Control System) implemented in a service control. The OCS operates on a controller of the image forming apparatus, and mainly conducts a process for accepting a user's operation, a drawing process for displaying screens corresponding to various applications, and other processes.
Accordingly, the application makes the display apparatus display a screen by calling a drawing function provided by the OCS.
Accordingly, every time when a function is switched to another function, an application corresponding to the another function is required to display a screen by calling the drawing function. In this case, a workload is required for a process to execute the application, and an usability of a user is influenced.
Accordingly, in the conventional image forming apparatus, in order to display a screen at the display apparatus, it is required to customize a program realizing each function of the application by corresponding to display contents and a screen layout, so as to call a necessary drawing function.
Therefore, for example, a modification of a function specification which influences the display contents and the screen layout is an extra workload for a developer. Moreover, functions are not easily provided to other software vendors (hereinafter, called “third vendors”).
Furthermore, the display components (for example, an “OK” button, a “cancel” button, and a like) to be displayed at the display screen of each function cannot be effectively managed as software resources.